1. Field of the Invention
The present invention relates to a user interface technique for an information processing device, and particularly to a handwriting type input display device according to a handwriting input display technique in which "operability of paper and pen" (which is defined as the same operability as performed by handwriting information on physical paper with a physical pen) is achieved by an information processing device.
2. Description of the Related Art
A handwriting type input display device to achieve "operability of paper and pen" has been hitherto utilized as a user interface for a general user because it can be easily operated by even an user who is unfamiliar with the operation of the information processing device. However, since such a conventional handwriting type input display device cannot sufficiently reproduce "the operability of paper and pen", there is a problem that the operational load imposed on the user is large and thus the operation efficiency of the user is low.
This problem will be described in detail by considering some specific prior art.
As a first prior art, there is known a handwriting type input display device such as a pen computer or a pen electronic pocketbook in which the coordinate value of a coordinate point detected by coordinate input means (corresponding to input means shown in FIGS. 1 to 3) such as a touch panel or the like is interpreted by processing means, and then a response display based on the interpretation is performed by display means such as LCD (Liquid Crystal Display) or the like.
In such a handwriting type input display device, there is a time delay from the time when a user performs his handwriting input operation until the time when a response display to the handwriting input operation is actually performed by the display means, and thus the user must carry out his handwriting input operation while considering that a curved line which does not appear at the input time (a curved line which is not displayed on the screen of the display means) will be displayed in time. This consideration would put mentally and realistically heavy operational load on the user. In addition, since the sampling interval of the coordinate input means is generally longer than the speed of the handwriting operation which is daily carried out by the user, a curved line which is handwritten by the user is actually broken in a response display step even by smoothly shifting a pen. Therefore, in order for the user to draw a curved line accurately, he must slowly shift the pen in consideration of the sampling interval, which causes the operation efficiency of the user to be reduced.
In the specification, an equipment to be held by an user to perform the handwriting input is called as "pen" (even if another name is provided to an equipment having the same function, the equipment is assumed to be covered by the concept of "pen").
As a second prior art, there is a handwriting input display device disclosed in Japanese Laid-open Patent Application No. Hei-6-289993. In order to solve the problem of the time delay of the response display in the first prior art, according to the second prior art, the coordinate value of a coordinate point which is predicted as a coordinate point to be input next is generated on the basis of the sequence of coordinate points (hereinafter referred to as a coordinate point sequence) obtained by coordinate input means, and then the response display of the coordinate point thus predicted is performed earlier by the delay time. If the position error (displacement) between the predicted coordinate point and the actually input coordinate point is large, the response display of the predicted coordinate point is deleted and the response display of the actually input coordinate point is performed again.
In the handwriting type input display device as described above, it is difficult to perform an accurate prediction on the basis of the sequence of the coordinate points which are obtained by the coordinate input means having a long sampling interval. In addition, the processing time is wasted because the response display must be carried out while repeating the deletion of predicted coordinate points which do not meet the actually input coordinate points as described above, and thus it is impossible to perform a continuous response display along a handwritten locus of a pen. This causes a user to be confused in the course of his handwriting operation, resulting in reduction of the operation efficiency.
As described above, in the above-described handwriting type input display devices, there are some problems that the operational load on the user is large and that the operation efficiency is low. That is, as described above, the first prior art has the problem that the operation load on the user is large because the response display to the handwriting input operation has a time delay, namely, time lag. The first prior art also has the problem that the operation efficiency of the user is low because the sampling interval of the coordinate input means is long. Furthermore, the second prior art has the problem that the processing time is wasted by the retrial of the response display for the deletion of a predicted coordinate point and it is impossible to perform a continuous response display along a locus of a pen, so that the operation efficiency of the user is reduced.